Index: branches/5.2.x/core/admin_templates/js/jquery/thickbox/thickbox.js
===================================================================
diff -u -N -r15530 -r15794
--- branches/5.2.x/core/admin_templates/js/jquery/thickbox/thickbox.js	(.../thickbox.js)	(revision 15530)
+++ branches/5.2.x/core/admin_templates/js/jquery/thickbox/thickbox.js	(.../thickbox.js)	(revision 15794)
@@ -115,11 +115,7 @@
 			}
 		}
 
-		if (TB.detectMacXFF()) {
-			$('#TB_overlay').addClass('TB_overlayMacFFBGHack'); // use png overlay so hide flash
-		} else {
-			$('#TB_overlay').addClass('TB_overlayBG'); // use background and opacity
-		}
+		$('#TB_overlay').addClass('TB_overlayBG'); // use background and opacity
 
 		if (params.caption === null) {
 			params.caption = '';
@@ -707,12 +703,6 @@
 	return [w, h];
 }
 
-TB.detectMacXFF = function () {
-	var userAgent = navigator.userAgent.toLowerCase();
-
-	return userAgent.indexOf('mac') != -1 && userAgent.indexOf('firefox') != -1;
-}
-
 TB.updateZIndex = function () {
 	// #TB_overlay - 1000100
 	// .TB_window - 1000102 [ok]